Diabetes is a clinically familiar chronic metabolic disease all over the world. In recent years, the world-wide morbidity rate of diabetes is rising rapidly along with the economic development and changes in dietary structure. According to statistics, the total number of diabetic patients can be 120 millions, among which more than 30 millions are Chinese. Most of the patients are insulin-independent, i.e., type II diabetes. At present, diabetes has become the third severe disease threatening the health of humans following cardiovascular disease and cancer. The duration of illness for diabetes is long and its complications occur usually during inadequate treatment, such as chronic vascular complications (including cerebrovascular disorders, ischemic heart disease), diabetic nephropathy, and so on. The mortality due to diabetes and its complications is also elevating year after year. Therefore, treatment and prevention of diabetes and its complications have become a key research task confronting medical and pharmaceutical workers of the world.
At present, the clinically used oral hypoglycemic agents are mainly Western drugs, which can be classified by their chemical structures as: sulfonylureas, biguanides, phenylalanines, thiazolidyldiketones, and glycolipids. Besides, there are 1,2-stilbene compounds which are now in research and development. According to the reports of U.S. Pat. No. 6,410,596 and CN1398838A, 1,2-stilbene compounds are present in many kinds of plants. Up to now, at least several decades of plants of 31 genues in 21 families are found to contain these compounds. At the meantime, these compounds are found to have extensive physiologic functions, such as anti-oxidation, anti-tumor, anti-blood stasis syndrome, hypoglycemic effect, and so forth. However, the 1,2-stilbenes having the above-mentioned functions are all trans-1,2-substituted stilbene derivatives. Concerning the activity of cis-1,2-substituted stilbene derivatives, only U.S. Pat. No. 5,525,632 reported that combrotastatin and its derivatives possessed anti-tumor function.